Zeolite SSZ-52x

ABSTRACT

The present invention relates to new crystalline zeolite SSZ-52x prepared using a quaternary ammonium cation templating agent, for example, having the structure: 
     
       
         
         
             
             
         
       
         
         
           
             wherein X −  is an anion which is not detrimental to the formation of the SSZ-52x. SSZ-52x is useful as a catalyst and shows improved durability, particularly with regard to NO x  conversion.

FIELD

The present invention relates to new crystalline zeolite SSZ-52x, amethod for preparing SSZ-52x using a quaternary ammonium cationtemplating agent such as, for example,N,N-diethyl-5,8-dimethyl-2-azonium bicyclo[3.2.2]nonane, and processesemploying SSZ-52x as a catalyst.

STATE OF THE ART

Because of their unique sieving characteristics, as well as theircatalytic properties, crystalline molecular sieves and zeolites areespecially useful in applications such as hydrocarbon conversion, gasdrying and separation. Although many different crystalline molecularsieves have been disclosed, there is a continuing need for new zeoliteswith desirable properties for gas separation and drying, hydrocarbon andchemical conversions, and other applications. New zeolites may containnovel internal pore architectures, providing enhanced selectivities inthese processes.

U.S. Pat. No. 6,254,849 describes zeolite SSZ-52, its compositionpreparation and useful applications. U.S. Pat. No. 6,379,531 describesprocesses using SSZ-52. For example, SSZ-52 is useful as an absorbentfor gas separation, and as a catalyst for reduction of NO_(x) in gasstreams or for methanol-to-olefins conversion.

Novel zeolites which can provide improved results in importantapplications such as NO_(x) reduction are always significant and welcometo the industry.

SUMMARY

The present invention is directed to a family of crystalline molecularsieves with unique properties, referred to herein as “zeolite SSZ-52x”or simply “SSZ-52x”. Preferably, SSZ-52x is obtained in itsaluminosilicate form. As used herein, the term “aluminosilicate” refersto a zeolite containing both alumina and silica.

In accordance with this invention, there is provided a zeolite having amole ratio of about 6-50 of an oxide selected from silicon oxide,germanium oxide and mixtures thereof to an oxide selected from aluminumoxide, gallium oxide, iron oxide, and mixtures thereof and having, aftercalcination, the X-ray diffraction lines of Table III below. In oneembodiment, the zeolite exhibits a NO_(x) conversion of 100% at 250° C.after aging at 750° C. for 80 hours at 10% humidity. In essence, SSZ-52xshows better 900° C. durability as compared to the standard SSZ-52xmaterial.

The present invention further provides such a zeolite having acomposition, as synthesized and in the anhydrous state, in terms of moleratios as follows:

TABLE I YO₂/W₂O₃  6-50 M_(2/n)/YO₂ 0.1-0.5 Q/YO₂ 0.01-0.08wherein Y is silicon, germanium or a mixture thereof; W is aluminum,gallium, iron, or mixtures thereof; M is an alkali metal cation,alkaline earth metal cation or mixtures thereof, n is the valence of M(i.e., 1 or 2); and Q is a quaternary ammonium cation having thestructure

In one embodiment, the organic structure directing agent is selectedfrom the group consisting of anN-ethyl-N-(2,4,4-trimethylcyclopentyl)pyrrolidinium cation, anN-ethyl-N-(3,3,5-trimethylcyclohexyl)pyrrolidinium cation, and mixturesthereof. The N-ethyl-N-(2,4,4-trimethylcyclopentyl)pyrrolidinium cationand the N-ethyl-N-(3,3,5-trimethylcyclohexyl)pyrrolidinium cation arerepresented by the following structures (2) and (3), respectively:

The zeolite has, after calcination, the X-ray diffraction lines of TableIII below.

In accordance with this invention, there is also provided a zeoliteprepared by thermally treating a zeolite having a mole ratio of an oxideselected from silicon oxide, germanium oxide and mixtures thereof to anoxide selected from aluminum oxide, gallium oxide, iron oxide, andmixtures thereof of about 6-50 at a temperature of from about 200° C. toabout 800° C. The present invention also includes this thus-preparedzeolite which is predominantly (at least 90%) in the hydrogen form,which hydrogen form is prepared by ion exchanging with an acid or with asolution of an ammonium salt followed by a second calcination.

Also provided in accordance with the present invention is a method ofpreparing a crystalline material comprising an oxide of a firsttetravalent element and an oxide of a second tetravalent element whichis different from said first tetravalent element, trivalent element,pentavalent element or mixture thereof, said method comprisingcontacting under crystallization conditions sources of said oxides and atemplating agent comprising the structures (1), (2), or (3), and withthe ratio of Q/YO₂ being in the range of from 0.01-0.05, in oneembodiment 0.015-0.03, and the ratio of M_(2/n)/YO₂ being in the rangeof from 0.51-0.90, in one embodiment from 0.60-0.90, Q is one or amixture of the templating agents, M is an alkaline metal cation,alkaline earth metal cation, or a mixture thereof, n is the valence ofM, and Y is silicon, germanium or a mixture thereof.

Also provided is an improved process for the reduction of oxides ofnitrogen contained in a gas stream in the presence of oxygen whereinsaid process comprises contacting the gas stream with a zeolite, theimprovement comprising using as the zeolite the zeolite of thisinvention. The zeolite may contain a metal or metal ions (such ascobalt, copper or mixtures thereof) capable of catalyzing the reductionof the oxides of nitrogen, and may be conducted in the presence of astoichiometric excess of oxygen. In a preferred embodiment, the gasstream is the exhaust stream of an internal combustion engine. It hasbeen found that SSZ-52x exhibits surprising stability in NO_(x)reduction.

Also provided in one embodiment is a process for converting loweralcohols and other oxygenated hydrocarbons comprising contacting saidlower alcohol or other oxygenated hydrocarbon with a catalyst comprisingthe zeolite of this invention under conditions to produce liquidproducts.

Also provided in accordance with one embodiment is a process for theseparation of gases, for example, nitrogen from a nitrogen-containinggas mixture, the process comprising contacting the mixture with acomposition comprising the zeolite of this invention. In one embodiment,the gas mixture contains nitrogen and methane.

BRIEF DESCRIPTION OF THE FIGURES OF THE DRAWING

FIG. 1 graphically illustrates NO_(x) conversion based on temperaturefor fresh catalyst comprising SSZ-52 and SSZ-52x.

FIG. 2 graphically illustrates NO_(x) conversion based on temperaturefor SSZ-52 and SSZ-52x catalyst aged at 750° C. for 80 hr in 10% H₂O.

FIG. 3(a) shows the RED data for SSZ-52x, and FIG. 3(b) shows the REDdata for SSZ-52.

FIG. 4(a) shows the powder X-ray diffraction (XRD) pattern ofas-synthesized SSZ-52x zeolite; and FIG. 4(b) shows the powder X-raydiffraction (XRD) pattern of as-synthesized SSZ-52 zeolite.

DETAILED DESCRIPTION

SSZ-52x is prepared from a reaction mixture having the composition shownin Table II below:

TABLE II Reaction Mixture YO₂/W₂O₃ 15-60 OH—/YO₂ 0.30-1.0  Q/YO₂ 0.01-0.05, preferably 0.015-0.03  M_(2/n)/YO₂  0.51-0.90, preferably0.60-0.90 H₂O/YO₂ 15-50where Y, W, Q, M and n are as defined above. It is important to maintainthe Q/YO₂ and M_(2/n)/YO₂ ratios within the noted ranges, otherwiseSSZ-52x would not be obtained.

In practice, SSZ-52x is prepared by a process comprising:

(a) preparing an aqueous solution containing sources of at least oneoxide capable of forming a crystalline molecular sieve and a templatingagent, or mixture of templating agents comprised of structures (1), (2),or (3). It has been found that the ratios of components in the reactionmixture must be within those noted in Table II above in order to obtainSSZ-52x.

(b) maintaining the aqueous solution under conditions sufficient to formcrystals of SSZ-52x; and

(c) recovering the crystals of SSZ-52x.

Accordingly, SSZ-52x may comprise the crystalline material and thetemplating agent in combination with metallic and non-metallic oxidesbonded in tetrahedral coordination through shared oxygen atoms to form across-linked three dimensional crystal structure. The metallic andnon-metallic oxides comprise one or a combination of oxides of a firsttetravalent element(s), and one or a combination of a second tetravalentelement(s) different from the first tetravalent element(s), trivalentelement(s), pentavalent element(s) or mixture thereof. The firsttetravalent element(s) is preferably selected from the group consistingof silicon, germanium and combinations thereof. More preferably, thefirst tetravalent element is silicon. The second tetravalent element(which is different from the first tetravalent element), trivalentelement and pentavalent element is preferably selected from the groupconsisting of aluminum, gallium, iron, and combinations thereof. Morepreferably, the second trivalent or tetravalent element is aluminum.

Typical sources of aluminum oxide for the reaction mixture includealuminates, alumina, aluminum colloids, aluminum oxide coated on silicasol, hydrated alumina gels such as Al(OH)₃ and aluminum compounds suchas AlCl₃ and Al₂(SO₄)₃. Typical sources of silicon oxide includesilicates, silica hydrogel, silicic acid, fumed silica, colloidalsilica, tetra-alkyl orthosilicates, and silica hydroxides. Gallium,germanium, and iron, can be added in forms corresponding to theiraluminum and silicon counterparts.

A source zeolite reagent may provide a source of aluminum or boron. Inmost cases, the source zeolite also provides a source of silica. Thesource zeolite in its dealuminated or deboronated form may also be usedas a source of silica, with additional silicon added using, for example,the conventional sources listed above. Use of a source zeolite reagentas a source of alumina for the present process is more completelydescribed in U.S. Pat. No. 4,503,024 issued on Mar. 5, 1985 to Bourgogneet al. entitled “Process for the Preparation of Synthetic Zeolites, andZeolites Obtained By Said Process”, the disclosure of which isincorporated herein by reference.

Typically, an alkali metal hydroxide and/or an alkaline earth metalhydroxide, such as the hydroxide of sodium, potassium, lithium, cesium,rubidium, calcium, and magnesium, is used in the reaction mixture;however, this component can be omitted so long as the equivalentbasicity is maintained. The templating agent may be used to providehydroxide ion. Thus, it may be beneficial to ion exchange, for example,the halide for hydroxide ion, thereby reducing or eliminating the alkalimetal hydroxide quantity required. The alkali metal cation or alkalineearth cation may be part of the as-synthesized crystalline oxidematerial, in order to balance valence electron charges therein.

The reaction mixture can also contain seeds of a molecular sievematerial, such as SSZ-52, desirably in an amount of from 0.01 to 50,000ppm by weight (e.g., from 100 to 5000 ppm by weight) of the reactionmixture.

One organic templating agent that can be used to prepare SSZ-52xcomprises an N,N-diethyl-5,8-dimethyl-2-azonium bicyclo[3.2.2]nonanecation having the following structure (1):

where X is an anion that is not detrimental to the formation of theSSZ-52x. Representative anions include halogen, e.g., fluoride,chloride, bromide and iodide, hydroxide, acetate, sulfate,tetrafluoroborate, carboxylate, and the like. Hydroxide is the mostpreferred anion.

In one embodiment, the organic structure directing agent is selectedfrom the group consisting of anN-ethyl-N-(2,4,4-trimethylcyclopentyl)pyrrolidinium cation, anN-ethyl-N-(3,3,5-trimethylcyclohexyl)pyrrolidinium cation, and mixturesthereof. The N-ethyl-N-(2,4,4-trimethylcyclopentyl)pyrrolidinium cationand the N-ethyl-N-(3,3,5-trimethylcyclohexyl)pyrrolidinium cation arerepresented by the following structures (2) and (3), respectively:

Any one of the organic templating agents having structures (1), (2), and(3) can be used to prepare SSZ-52x, or a mixture of the templatingagents can be used.

The reaction mixture is maintained at an elevated temperature until thecrystals of the SSZ-52x zeolite are formed. The hydrothermalcrystallization is usually conducted under autogenous pressure, at atemperature between 120° C. and 160° C. The crystallization period istypically greater than 1 day and preferably from about 3 days to about20 days.

Preferably, the zeolite is prepared using mild stirring or agitation.

During the hydrothermal crystallization step, the SSZ-52x crystals canbe allowed to nucleate spontaneously from the reaction mixture. The useof SSZ-52 or SSZ-52x crystals as seed material can be advantageous indecreasing the time necessary for complete crystallization to occur. Inaddition, seeding can lead to an increased purity of the productobtained by promoting the nucleation and/or formation of SSZ-52x overany undesired phases. When used as seeds, SSZ-52 crystals are added inan amount between 0.1 and 10% of the weight of silica used in thereaction mixture.

Once the zeolite crystals have formed, the solid product is separatedfrom the reaction mixture by standard mechanical separation techniquessuch as filtration. The crystals are water-washed and then dried, e.g.,at 90° C. to 150° C. for from 8 to 24 hours, to obtain theas-synthesized SSZ-52x zeolite crystals. The drying step can beperformed at atmospheric pressure or under vacuum.

SSZ-52x as prepared has a mole ratio of an oxide selected from siliconoxide, germanium oxide and mixtures thereof to an oxide selected fromaluminum oxide, gallium oxide, iron oxide, and mixtures thereof of about6-50; and has, after calcination, the X-ray diffraction lines of TableIII below. SSZ-52x further has a composition, as synthesized and in theanhydrous state, in terms of mole ratios, shown in Table I below.

TABLE I As-Synthesized SSZ-52x YO₂/W₂O₃  6-50 M_(2/n)/YO₂ 0.1-0.5 Q/YO₂0.01-0.08where Y, W, Q, M and n are as defined above. It has also been found thatthe SSZ-52x prepared exhibits surprisingly improved stability andperformance with regard to NO_(x) conversion such that NO_(x) conversionof 100% at 250° C. is achieved even after aging at 750° C. for 80 hoursat 10% humidity. Such performance is an unexpected improvement overprior art zeolite SSZ-52, underscoring the difference between SSZ-52 andSSZ-52x. See, FIGS. 1 and 2.

It is believed that SSZ-52x is comprised of a novel structure ofincreased disorder compared to SSZ-52 which is characterized by itsX-ray diffraction pattern and rotation electron diffraction. Forexample, samples of SSZ-52 and SSZ-52x were analyzed by the rotationelectron diffraction (RED) technique where 3-dimensional electrondiffraction data on nanometer-sized single crystals can be recorded.

Four RED datasets for each sample were collected under the sameexperimental settings: the crystal was tilted a total of 100°, electrondiffraction images were collected every 0.3° of tilt change.

To estimate the disorder level of the structures of both SSZ-52 andSSZ-52x, the ratio of the number of diffraction streaks (diffractionfeature representing disordered structure) and the number of diffractionspots (diffraction feature representing ordered structure) werecalculated and listed in Table III below. This clearly demonstrates thatSSZ-52x crystals are characterized by a significantly higher level ofdisorder than SSZ-52 crystals.

FIG. 3(a) is a picture of the RED data for SSZ-52x and FIG. 3(b) is apicture of the RED data for SSZ-52.

TABLE III RED RED RED RED data −1 data −2 data −3 data −4 SSZ-52x num.streaks 12081 6926 8091 7402 num. spots 1199 2545 1177 3122 ratio 10.082.72 6.87 2.37 SSZ-52 num. streaks 2084 447 2220 2041 num. spots 37073364 2989 3650 ratio 0.56 0.13 0.74 0.56

After calcination, the SSZ-52x zeolites have a crystalline structurewhose X-ray powder diffraction pattern includes the characteristic linesshown in Table IV:

TABLE IV Characteristic Peaks for Calcined SSZ-52x 2-Theta(a) d-Spacing,nm Relative Intensity(b) 7.68 1.150 S 8.46 1.044 M 10.96 0.806 S 12.300.719 M 12.96 0.683 VS 15.08 0.587 W 17.06 0.519 W 17.88 0.496 VS 19.940.445 VS 20.26 0.438 VS 21.46 0.414 VS 22.15 0.401 M 22.58 0.393 W(a)±0.20 degrees (b)The powder XRD patterns provided are based on arelative intensity scale in which the strongest line in the X-raypattern is assigned a value of 100: W = weak (>0 to ≤20); M = medium(>20 to ≤40); S = strong (>40 to ≤60); VS = very strong (>60 to ≤100).

The X-ray patterns provided are based on a relative intensity scale inwhich the strongest line in the X-ray pattern is assigned a value of100: W (weak) is less than 20; M (medium) is between 20 and 40; S(strong) is between 40 and 60; VS (very strong) is greater than 60.

Characteristic X-ray diffraction lines for as-synthesized SSZ-52x areshown in Table V below. FIG. 4(a) of the Drawing shows the XRD patternfor the as-synthesized form of SSZ-52x, as it compares to the XRDpattern for SSZ-52 shown in FIG. 4(b).

TABLE V Characteristic Peaks for As-Synthesized SSZ-52x. 2-Theta(a)d-Spacing, nm Relative Intensity(b) 7.60 1.162 S 8.48 1.041 W 10.960.806 W 12.40 0.714 S 12.98 0.681 M 15.12 0.585 M 17.00 0.521 M 17.860.496 VS 19.96 0.444 VS 20.28 0.438 M 21.52 0.413 VS 22.16 0.401 M 22.590.393 W (a)±0.20 degrees (b)The powder XRD patterns provided are basedon a relative intensity scale in which the strongest line in the X-raypattern is assigned a value of 100: W = weak (>0 to ≤20); M = medium(>20 to ≤40); S = strong (>40 to ≤60); VS = very strong (>60 to ≤100).

Representative peaks from the X-ray diffraction pattern of calcinedSSZ-52x are shown in Table III. Calcination can result in changes in theintensities of the peaks as compared to patterns of the “as-made”material, as well as minor shifts in the diffraction pattern. Thezeolite produced by exchanging the metal or other cations present in thezeolite with various other cations (such as H⁺ or NH₄ ⁻) yieldsessentially the same diffraction pattern, although again, there may beminor shifts in the interplanar spacing and variations in the relativeintensities of the peaks. Notwithstanding these minor perturbations, thebasic crystal lattice remains unchanged by these treatments.

Crystalline SSZ-52x can be used as-synthesized, but preferably will bethermally treated (calcined). Usually, it is desirable to remove thealkali metal cation by ion exchange and replace it with hydrogen,ammonium, or any desired metal ion. The zeolite can be leached withchelating agents, e.g., EDTA or dilute acid solutions, to increase thesilica to alumina mole ratio. The zeolite can also be steamed; steaminghelps stabilize the crystalline lattice to attack from acids.

Metals may also be introduced into the zeolite by replacing some of thecations in the zeolite with metal cations via standard ion exchangetechniques (see, for example, U.S. Pat. No. 3,140,249 issued Jul. 7,1964 to Plank et al.; U.S. Pat. No. 3,140,251 issued Jul. 7, 1964 toPlank et al.; and 3,140,253 issued Jul. 7, 1964 to Plank et al.).Typical replacing cations can include metal cations, e.g., rare earth,Group IA, Group IIA and Group VIII metals, as well as their mixtures. Ofthe replacing metallic cations, cations of metals such as rare earth,Mn, Ca, Mg, Zn, Cd, Pt, Pd, Ni, Cu, Co, Ti, Al, Sn, and Fe areparticularly preferred.

The hydrogen, ammonium, and metal components can be ion-exchanged intothe SSZ-52x. The zeolite can also be impregnated with the metals, or,the metals can be physically and intimately admixed with the zeoliteusing standard methods known to the art.

Typical ion-exchange techniques involve contacting the synthetic zeolitewith a solution containing a salt of the desired replacing cation orcations. Although a wide variety of salts can be employed, chlorides andother halides, acetates, nitrates, and sulfates are particularlypreferred. The zeolite is usually calcined prior to the ion-exchangeprocedure to remove the organic matter present in the channels and onthe surface, since this results in a more effective ion exchange.Representative ion exchange techniques are disclosed in a wide varietyof patents including U.S. Pat. No. 3,140,249 issued on Jul. 7, 1964 toPlank et al.; U.S. Pat. No. 3,140,251 issued on Jul. 7, 1964 to Plank etal.; and 3,140,253 issued on Jul. 7, 1964 to Plank et al.

Following contact with the salt solution of the desired replacingcation, the zeolite is typically washed with water and dried attemperatures ranging from 65° C. to about 200° C. After washing, thezeolite can be calcined in air or inert gas at temperatures ranging fromabout 200° C. to about 800° C. for periods of time ranging from 1 to 48hours, or more, to produce a catalytically active product especiallyuseful in hydrocarbon conversion processes.

Regardless of the cations present in the synthesized form of SSZ-52x,the spatial arrangement of the atoms which form the basic crystallattice of the zeolite remains essentially unchanged.

SSZ-52x can be formed into a wide variety of physical shapes. Generallyspeaking, the zeolite can be in the form of a powder, a granule, or amolded product, such as extrudate having a particle size sufficient topass through a 2-mesh (Tyler) screen and be retained on a 400-mesh(Tyler) screen. In cases where the catalyst is molded, such as byextrusion with an organic binder, the aluminosilicate can be extrudedbefore drying, or, dried or partially dried and then extruded.

SSZ-52x can be composited with other materials resistant to thetemperatures and other conditions employed in organic conversionprocesses. Such matrix materials include active and inactive materialsand synthetic or naturally occurring zeolites as well as inorganicmaterials such as clays, silica and metal oxides. Examples of suchmaterials and the manner in which they can be used are disclosed in U.S.Pat. No. 4,910,006, issued May 20, 1990 to Zones et al., and U.S. Pat.No. 5,316,753, issued May 31, 1994 to Nakagawa, both of which areincorporated by reference herein in their entirety.

NO_(x) Reduction

SSZ-52x is quite favorably used for the catalytic reduction of theoxides of nitrogen in a gas stream. Typically, the gas stream alsocontains oxygen, often a stoichiometric excess thereof. Also, theSSZ-52x may contain a metal or metal ions within or on it which arecapable of catalyzing the reduction of the nitrogen oxides. Examples ofsuch metals or metal ions include copper, cobalt, iron, and mixturesthereof.

One example of such a process for the catalytic reduction of oxides ofnitrogen in the presence of a zeolite is disclosed in U.S. Pat. No.4,297,328, issued Oct. 27, 1981 to Ritscher et al., which isincorporated by reference herein. There, the catalytic process is thecombustion of carbon monoxide and hydrocarbons and the catalyticreduction of the oxides of nitrogen contained in a gas stream, such asthe exhaust gas from an internal combustion engine. The zeolite used ismetal ion-exchanged, doped or loaded sufficiently so as to provide aneffective amount of catalytic copper metal or copper ions within or onthe zeolite. In addition, the process is conducted in an excess ofoxidant, e.g., oxygen.

It has been found that the SSZ-52x provides enhanced performance withregard to NO_(x) conversion compared to SSZ-52, for example. SSZ-52x ismore stable as the aged catalyst has been observed to provide improvedNO_(x) conversion at a lower temperature, e.g., 100% at 250° C., ascompared to SSZ-52. This is shown in FIGS. 1 and 2 of the Drawing.

Hydrocarbon Conversion Processes

SSZ-52x zeolites are useful in hydrocarbon conversion reactions.Hydrocarbon conversion reactions are chemical and catalytic processes inwhich carbon containing compounds are changed to different carboncontaining compounds. Examples of hydrocarbon conversion reactions inwhich SSZ-52x are expected to be useful include hydrocracking, dewaxing,catalytic cracking and olefin formation reactions. The catalysts arealso expected to be useful in other petroleum refining and hydrocarbonconversion reactions such as isomerizing n-paraffins and naphthenes,isomerizing olefins, polymerizing and oligomerizing olefinic oracetylenic compounds such as isobutylene and butene-1, reforming,forming higher molecular weight hydrocarbons from lower molecular weighthydrocarbons (e.g., methane upgrading) and oxidation reactions. TheSSZ-52x catalysts may have high selectivity, and under hydrocarbonconversion conditions can provide a high percentage of desired productsrelative to total products.

SSZ-52x zeolites can be used in processing hydrocarbonaceous feedstocks.Hydrocarbonaceous feedstocks contain carbon compounds and can be frommany different sources, such as virgin petroleum fractions, recyclepetroleum fractions, shale oil, liquefied coal, tar sand oil, syntheticparaffins from NAO, recycled plastic feedstocks and, in general, can beany carbon containing feedstock susceptible to zeolitic catalyticreactions. Depending on the type of processing the hydrocarbonaceousfeed is to undergo, the feed can contain metal or be free of metals, itcan also have high or low nitrogen or sulfur impurities. It can beappreciated, however, that in general processing will be more efficient(and the catalyst more active) the lower the metal, nitrogen, and sulfurcontent of the feedstock.

The conversion of hydrocarbonaceous feeds can take place in anyconvenient mode, for example, in fluidized bed, moving bed, or fixed bedreactors depending on the types of process desired. The formulation ofthe catalyst particles will vary depending on the conversion process andmethod of operation.

Molecular sieve SSZ-52x may be suitable for use as a catalyst in theconversion of oxygenates to olefins. As used herein, the term“oxygenates” is defined to include, but is not necessarily limited toaliphatic alcohols, ethers, carbonyl compounds (e.g., aldehydes,ketones, carboxylic acids, carbonates, and the like), and also compoundscontaining hetero-atoms, such as, halides, mercaptans, sulfides, amines,and mixtures thereof. The aliphatic moiety will normally contain from 1to 10 carbon atoms (e.g., from 1 to 4 carbon atoms). Particularlysuitable oxygenate compounds are methanol, dimethyl ether, or mixturesthereof, especially methanol.

Conversion of oxygenates may be carried out with the oxygenate (e.g.,methanol) in the liquid or the vapor phase, in batch or continuous mode.When carried out in continuous mode, a weight hourly space velocity(WHSV), based on oxygenate, of 1 to 1000 h⁻¹ (e.g., 1 to 100 h⁻¹) may beused. An elevated temperature is generally required to obtain economicconversion rates (e.g., a temperature between 300° C. and 600° C. orbetween 400° C. and 500° C.). The catalyst may be in a fixed bed, or adynamic, e.g., fluidized or moving, bed.

The oxygenate feedstock may be mixed with a diluent, inert under thereaction conditions (e.g., argon, nitrogen, carbon dioxide, hydrogen, orsteam). The concentration of oxygenate in the feedstream may vary widely(e.g., from 5 to 90 mole percent of the feedstock). The pressure mayvary within a wide range (e.g., from atmospheric to 500 kPa).

The olefin(s) produced typically have from 2 to 30 carbon atoms (e.g.,from 2 to 8 carbon atoms, from 2 to 6 carbon atoms, or from 2 to 4carbons atoms, and most preferably are ethylene and/or propylene).

Other reactions which can be performed using the catalyst of thisinvention containing a metal, e.g., a Group VIII metal such platinum,include hydrogenation-dehydrogenation reactions, denitrogenation anddesulfurization reactions.

The following Table VI indicates typical reaction conditions which maybe employed when using catalysts comprising SSZ-52x in the hydrocarbonconversion reactions of this invention. Preferred conditions areindicated in parentheses.

TABLE VI Process Temp., ° C. Pressure LHSV Hydrocracking 175-485 0.5-350bar 0.1-30 Dewaxing 200-475 15-3000 psig 0.1-20 (250-450) (200-3000)(0.2-10) Cat. Cracking 127-885 subatm.—¹ 0.5-50  (atm.-5 atm.)Oligomerization  232-649² 0.1-50 atm.^(2,3)  0.2-50²   10-232⁴ —0.05-20⁵    (27-204)⁴ —  (0.1-10)⁵ Condensation of 260-538 0.5-1000 psig 0.5-50⁵ alcohols Isomerization  93-538 50-1000 psig  1-10 (204-315) (1-4) ¹Several hundred atmospheres ²Gas phase reaction ³Hydrocarbonpartial pressure ⁴Liquid phase reaction ⁵WHSVOther reaction conditions and parameters are provided below.Catalytic Cracking

Hydrocarbon cracking stocks can be catalytically cracked in the absenceof hydrogen using SSZ-52x, typically predominantly in the hydrogen form.

When SSZ-52x is used as a catalytic cracking catalyst in the absence ofhydrogen, the catalyst may be employed in conjunction with traditionalcracking catalysts, e.g., any aluminosilicate heretofore employed as acomponent in cracking catalysts. Typically, these are large pore,crystalline aluminosilicates. Examples of these traditional crackingcatalysts are disclosed in the aforementioned U.S. Pat. Nos. 4,910,006and 5,316,753. When a traditional cracking catalyst (TC) component isemployed, the relative weight ratio of the TC to the SSZ-52x isgenerally between about 1:10 and about 500:1, desirably between about1:10 and about 200:1, preferably between about 1:2 and about 50:1, andmost preferably is between about 1:1 and about 20:1. The novel zeoliteand/or the traditional cracking component may be further ion exchangedwith rare earth ions to modify selectivity.

The cracking catalysts are typically employed with an inorganic oxidematrix component. See the aforementioned U.S. Pat. Nos. 4,910,006 and5,316,753 for examples of such matrix components.

Other Uses for SSZ-52x

SSZ-52x can also be used as an adsorbent based on molecular sievebehavior.

SSZ-52x may also be used in the separation of gases, such as theseparation of nitrogen from a nitrogen-containing gas mixture. Oneexample of such separation is the separation of nitrogen from methane(e.g., the separation of nitrogen from natural gas).

EXAMPLES

The following examples demonstrate but are not intended to be limiting.

Example 1

Synthesis of N,N-diethyl-5,8-dimethyl-2-azonium bicyclo[3.2.2]nonanecation (Templating Agent of Structure (1)).

A three-neck, 5-liter flask is set up with additional funnel withequalization arm. A septum is place over the funnel. Nitrogen is passedthrough the system. First an in-situ reagent is developed by placing104.55 grams of diisopropylamine in 1859 ml of tetrahydrofuran (THF) andthen slowly adding 401.7 ml of n-butyl lithium (2.5 M in hexane) whilekeeping the temperature near −70° C. The n-butyl lithium is charged tothe addition funnel by use of a cannula. The addition into THF takesabout 1.25 hours after which the resulting mixture is stirred foranother hour. 104.53 grams of 3-methyl-2-cyclohexene-1 one in 1117 mlTHF is added dropwise over a 0.75 hour period. Lastly, 161.73 grams ofmethyl acrylate is added over a period of 0.25 hour. Gradually, thereaction is allowed to warm to room temperature and its progress isfollowed by TLC. The reaction appears to go overnight.

Recovery of the product is begun by adding 1N HCl until the solutionbecomes acidic. The reaction product is transferred to separatory funneland the aqueous phase is recovered to subsequently treat with methylenechloride (2.times.250 ml). The combined organic phase is dried oversodium sulfate and then strip solvent. The residue is taken up in etherto free it from a little gummy material. The ether is removed and theresulting oil is distilled; a Vigreaux column (30 cm) is set up and runat 2-4 mm Hg. The bulk of the product comes over between 123-137° C.

The resulting product is reduced using lithium aluminum hydride. Thereduction produces a diol, 1-methyl-2-methanol-7-hydroxybicyclo[2.2.2]octane. The side methanol group is tosylated by reactionof tosyl chloride (96.92 grams) with the diol (85.68 grams) in anhydrouspyridine (500 ml). The tosyl chloride is added to the other twocomponents, under nitrogen, using a powder addition funnel while coolingthe reaction to −5° C. The addition is carried out over 0.75 hour andthe reaction mixture is warmed to room temperature and the reaction isallowed to run overnight. 500 ml of methylene chloride is added, theresulting mixture transferred to a separatory funnel, and washed withwater (2.times.250 ml). The resulting product is dried over sodiumsulfate, filtered, and stripped to yield 150 grams of oil.

The product is purified by column chromatography. A kilogram of silicagel (230-400 mesh) is slurried in hexane, and the oil is loaded on topin 50 ml methylene chloride. The elution is carried out using 25/75ethyl acetate (ETOAC); hexane and fractions are monitored by TLC.Eighty-three grams of product is collected. The tosylate is then reducedusing LAH (as above) to yield 1,2-dimethyl-7-hydroxybicyclo[2.2.2]octane. Next, the alcohol is reoxidized to the ketone.37.84 grams of the alcohol is reacted in a three-neck, 2-liter flask asfollows: 34.60 grams of oxalyl chloride and 604 ml of methylene chlorideare loaded in and blanketed under nitrogen. With an addition funnel withside arm, 46 grams of anhydrous dimethylsulfoxide (DMSO) in 122.7 ml ofmethylene chloride is added. The bath is cooled to −60° C. using a dryice/acetone bath, and the addition takes 0.5 hour. The alcohol, in 53.4ml methylene chloride, is added at this temperature over 0.5 hourfollowed by stirring for another 0.5 hour. 126.65 Grams of triethylamineis then placed in the addition funnel and addition begun and continuedover 0.25 hour. All of the additions produce exothermic response, socooling is continued. The reaction mixture is slowly warmed to roomtemperature and the reaction continued to run overnight.

Work-up of the reaction product begins with addition of 500 ml water.The separated aqueous phase is then extracted with methylene chloride(2.times.250 ml). The combined organic phases are then dried overmagnesium sulfate and stripped. The resulting oil is triturated withether to separate a small amount of insoluble material. Stripping offether yields 37 grams of product.

Thirty-seven grams of ketone and 240 ml of 96% formic acid are placedinto a 1 liter round bottom flask connected to an addition funnel. Thesecomponents are stirred using a magnetic stir bar. 125 Ml of formic acidwith 43 grams of hydroxylamine-O-sulfonic acid dissolved and suspendedin it, are added to the funnel. The addition is carried out over a 20minute period with stirring. The solution darkens. The addition funnelis replaced with a reflux condenser, and the reaction is refluxed for15-20 hours with samples taken to follow by TLC.

The mixture is carefully poured into 2 kg of ice. After cooling in theice, the mixture is slowly brought to pH=12 with the addition of 50%NaOH. Three extractions are carried out using 500 cc units of methylenechloride. These extracts are dried over sodium sulfate. After drying,the solvent is stripped off leaving a black oil of about 45 grams.

This oil is dissolved in a minimum of chloroform and loaded onto acolumn (750 grams of 230-400 mesh silica gel, already slurried inchloroform). The elution progresses using chloroform with 2 vol. %methanol. The elution fractions are followed by TLC (fractions 7-21 givethe same product). The similar fractions are combined and removing theeluting solvent yields about 30 grams of lactam.

25 Grams of this lactam is used in the reduction step. Using a 2 liter3-neck round bottom flask, nitrogen gas is run into the system andvented up through the reflux condenser and into a bubbler. The systemhas an addition funnel. 460 Ml of anhydrous ether are added into theflask. Carefully, 18 grams of lithium aluminum hydride are also admittedinto the flask. There is some gas evolution. The lactam is dissolved in230 ml of methylene chloride (also anhydrous). After cooling the flaskdown in an acetone/dry ice bath, the lactam is added dropwise. Thereaction is exothermic so periodically more ice needs to be added astemperature rises. The reduction can be followed by change in TLC data(monitored by iodine and eluted on silica with 98/2chloroform/methanol). The reaction is allowed to come to roomtemperature overnight.

18 Grams of water are slowly added with the expected exothermicevolution of gas occurring. The ether is removed and its volume replacedwith dichloromethane. 18 Grams of 15% NaOH solution and then 55 grams ofwater are added. The solids which form are filtered off, washed withadditional dichloromethane, and combined with the organic fractions anddry over sodium sulfate (Caution: Do not let the NaOH solution sit incontact with dichloromethane overnight.). The solvent is stripped off torecover about 15 grams of oil/solid mix. This is the crude amine.

10 grams of this amine is quaternized as follows: In a 250 ml flaskequipped with stir bar and reflux condenser add the amine, 10 grams ofKHCO3, 65 ml of methanol and lastly, 30 grams of ethyl iodide. Themixture is brought to reflux and maintained in that state for 48 hours.Upon cooling, the solvent is removed. The solids are treated withchloroform. In turn the chloroform-soluble fractions are stripped toyield another solid which is recrystallized from a minimum of hotacetone and methanol. Recrystallization in the cold yields 3 separatecrops of product, totaling 11 grams of the salt. The melting points forthese crops are all in the range of 252-256° C.

The salt is converted to the hydroxide form by ion-exchange over aBioRad AG1-X8 resin.

Example 2 Synthesis of N-ethyl-N-(3,3,5-trimethylcyclohexyl)pyrrolidinium cation Synthesis of N-(3,3,5-Trimethylyyclohexyl)Pyrrolidine

The structure-directing agent (SDA) is synthesized using the reactionsequence described in the scheme below.

Synthesis of the Parent Amine N-(3,3,5-trimethylcyclohexyl)pyrrolidine

In a 3-liter three neck flask a 150 gm (2.13 mole) of pyrrolidine, 100gm of 3,5,5-trimethylcyclohexanone (0.71 mole) are mixed in a 1500 mlanhydrous hexane. To the resulting solution, 150 gm (1.25 mole) ofanhydrous magnesium sulfate is added and the mixture is mechanicallystirred and heated at reflux (the reaction is monitored by NMR analysis)for 132 hours. The reaction mixture is filtered through a fritted glassfunnel. The filtrate is concentrated under reduced pressure on a rotaryevaporator to give 133 gm of an isomeric mixture of the desired enamineas indicated by H¹NMR and C¹³-NMR analysis[(3,3,5-trimethylcyclohex-enyl)pyrrolidine and(3,3,5-trimethylcyclohex-enyl)pyrrolidine]. Saturation of the enaminemixture, to give N-(3,5,5-trimethylcyclohexyl)pyrrolidine, isaccomplished in quantitative yield by hydrogenation in ethanol at a 55psi pressure of hydrogen gas in the presence of 10% Pd on activatedcarbon.

Quaternization of N-(3,3,5-Trimethylcyclohexyl)Pyrrolidine (Synthesis ofN-Ethyl-N-(3,3,5-Trimethcyclohexyl)Pyrrolidinium Iodide)

To a solution of 131 gm (0.67 mole) ofN-(3,3,5-trimethylcyclohexyl)pyrrolidine in 1000 ml anhydrous methanol,210 gm (1.34 mole) of ethyl iodide is added. The reaction ismechanically stirred for 3 days at room temperature. Then, an additionalequivalent of ethyl iodide and one equivalent (67.7 gm; 0.0.67 mole) ofpotassium bicarbonate are added and the reaction is stirred at refluxingtemperature for 72 hours. The reaction mixture is concentrated underreduced pressure on a rotary evaporator to give an off-white-coloredsolid material. The solids are rinsed several times with chloroform andfiltered after each rinse. All the chloroform rinses are combined andconcentrated to give a white powder whose NMR data are acceptable forthe desired quaternary ammonium iodide salt. The reaction affords 218 gm(93% yield) of the product. The iodide salt is purified byre-crystallization in acetone and ether. This is done by completelydissolving the iodide salt in acetone and, then, the precipitation ofthe product is facilitated by addition of ethyl ether to the acetonesolution. Re-crystallization gives 211 gm of the product as white powder(pure by H¹ and C¹³-NMR NMR analysis).

Ion Exchange (Synthesis ofN-Ethyl-N-(3,3,5-Trimethylcyclohexyl)Pyrrolidinium Hydroxide)

To a solution of N-ethyl-N-(3,3,5-trimethylcyclohexyl)pyrrolidiniumiodide salt (100 gm; 0.285 mole) in 350 ml water in a 1-liter plasticbottle, 340 gm of Ion-Exchange Resin-OH (BIO RAD® AH1-X8) is added andthe mixture is gently stirred at room temperature overnight. The mixtureis filtered and the solids rinsed with additional 75 ml of water.Titration analysis with 0.1N HCl gives a total yield of 0.215 mole ofhydroxide ions (0.215 moleN-ethyl-N-(3,3,5-trimethylcyclohexyl)pyrrolidinium hydroxide).

Example 3 Synthesis ofN-Ethyl-N-(2,4,4-Trimethylcyclopentyl)Pyrrolidinium Cation

N-ethyl-N-(2,4,4,-trimethylcyclopentyl)pyrrolidinium cation issynthesized using the synthetic scheme described above starting frompyrrolidine and 2,4,4-trimethylcyclopentanone

Example 4 Synthesis of SSZ-52x

3.71 grams of an SDA having structure (1), anN,N-diethyl-5,8-dimethyl-2-azonium bicyclo [3.2.2] nonane cation, ismixed with 20.51 grams of water, 9.98 grams of 1N NaOH, 17.28 grams of asodium silicate solution, 0.18 grams of seed SSZ-52 crystals, and 1.75grams of sodium Y zeolite as a source of aluminum. The concentration ofSDA was 0.54M. All of the components were combined in a 125 cc PTFEliner. The liner was sealed in an autoclave and heated to 135° C. Theautoclave was rotated for four days.

A crystalline product was recovered and determined by X-ray diffractionto be SSZ-52x. The product had the XRD data of Table V and the X-raydiffraction pattern of FIG. 4(a).

Example 5 Synthesis of SSZ-52x

In a 23 mL PTFE autoclave liner, 1.39 mmol of N,N-diethyl-5,8-dimethyl-2-azonium bicyclo [3.2.2] nonane hydroxide (0.54M), 1.35 g of 1N NaOH solution, 2.59 g of sodium silicate solution, 2.49g of deionized water, 0.26 g of zeolite Y (CBV300, Zeolystinternational, SiO2/A1203 mole ratio=5.1), and 0.027 g of SSZ-52 seedswere combined and stirred until a homogenous mixture was obtained. Theliner was capped and placed within a Parr steel autoclave reactor. Theautoclave heated at 135° C. with rotation (43 rpm) for 4 days. Therecovered product was confirmed by XRD to be SSZ-52x.

Example 6 Calcination of SSZ-52x

The material from Example 4 is calcined in the following manner. A thinbed of material is heated in a muffle furnace from room temperature to120° C. at a rate of 1° C. per minute and held at 120° C. for threehours. The temperature is then ramped up to 540° C. at the same rate andheld at this temperature for 5 hours. A 50/50 mixture of air andnitrogen is passed over the zeolite at a rate of 20 standard cubic feetper minute during heating. The X-ray diffraction data for the productwas that of Table IV.

Example 7 NO_(x) Conversion

Calcined SSZ-52x was loaded with copper by weight via an incipientwetness process. The ion-exchanged material was then activated byincreasing the temperature of the material from room temperature to 150°C. at a rate of 2° C./minute, holding the material at 150° C. for 16hours, then increasing the temperature of the material to 450° C. at arate of 5° C./minute, holding the material at 450° C. for 16 hours. Thematerial was then allowed to cool to room temperature again.

The sample was tested to determine its capacity for NO_(x) conversion(e.g., into N₂ and O₂) as a function of temperature. Fresh (i.e.,un-aged) Cu/SSZ-52 was tested using a Synthetic Catalyst Activity Test(SCAT) rig under the following conditions: 500 ppm NO, 500 ppm NH₃, 10%O₂, 10% H₂O and the balance N₂; and a space velocity of 60,000/hour. Theresults are shown in FIG. 1. Aged catalyst, e.g., aged at 750° C. for 80hours in 10% (humidity), was also tested using SCAT as noted above. Theresults are shown in FIG. 2 and demonstrate the superior durability andenhanced performance of SSZ-52x compared to SSZ-52.

For the purposes of this specification and appended claims, unlessotherwise indicated, all numbers expressing quantities, percentages orproportions, and other numerical values used in the specification andclaims, are to be understood as being modified in all instances by theterm “about.” Furthermore, all ranges disclosed herein are inclusive ofthe endpoints and are independently combinable. Whenever a numericalrange with a lower limit and an upper limit are disclosed, any numberfalling within the range is also specifically disclosed.

As used herein, the term “comprising” means including elements or stepsthat are identified following that term, but any such elements or stepsare not exhaustive, and an embodiment can include other elements orsteps.

Unless otherwise specified, the recitation of a genus of elements,materials or other components, from which an individual component ormixture of components can be selected, is intended to include allpossible sub-generic combinations of the listed components and mixturesthereof.

Any term, abbreviation or shorthand not defined is understood to havethe ordinary meaning used by a skilled artisan at the time theapplication is filed. The singular forms “a,” “an,” and “the,” includeplural references unless expressly and unequivocally limited to oneinstance.

All of the publications, patents and patent applications cited in thisapplication are herein incorporated by reference in their entirety tothe same extent as if the disclosure of each individual publication,patent application or patent was specifically and individually indicatedto be incorporated by reference in its entirety.

What is claimed is:
 1. A zeolite SSZ-52x having a mole ratio of 6-50 ofan oxide selected from the group consisting of silicon oxide, germaniumoxide and mixtures thereof to an oxide selected from aluminum oxide,gallium oxide, iron oxide and mixtures thereof, and exhibiting in the assynthesized form the XRD pattern of FIG. 4(a).
 2. The zeolite SSZ-52xaccording to claim 1, wherein the oxides comprise silicon oxide andaluminum oxide.
 3. The zeolite SSZ-52x zeolite according to claim 1,wherein said zeolite is in the hydrogen form.
 4. The zeolite SSZ-52xaccording to claim 1, having a composition, as synthesized and in theanhydrous state, in terms of mole ratios as follows: YO₂/W₂O₃  6-50M_(2/n)/YO₂ 0.1-0.5 Q/YO₂ 0.01-0.08

wherein Y is silicon, germanium or a mixture thereof; W is aluminum,gallium, iron or mixtures thereof; M is an alkali metal cation, alkalineearth metal cation or mixtures thereof; n is the valence of M; and Q isa quaternary ammonium cation having the structure

where X− is an anion which is not detrimental to the formation of thezeolite.
 5. The zeolite SSZ-52x according to claim 4, wherein W isaluminum and Y is silicon.